The present invention relates to a bottle container made of resin for accommodating a liquid substance, the bottle container comprising a cylindrical neck portion on an upper end of a cylindrical barrel with a bottom, the neck portion having a diameter smaller than that of the barrel. The invention also relates to a method for manufacturing the bottle container. For instance, the invention relates to a bottle container made of resin for accommodating a liquefied cosmetic material such as mascara liquid and also to a method for manufacturing the bottle container.
In the past, a blow molding method has been used to manufacture a bottle container made of resin, which comprises a cylindrical barrel with a bottom and a cylindrical neck portion having a diameter smaller than that of the barrel (e.g. JP-A-2001-113589). However, by this blow molding method, it has been only possible to manufacture a bottle container with portions other than the neck portion having 3 mm in thickness at the most. It has been difficult to mold a bottle container of about 5 mm in thickness. Also, by this blow molding method, it has been difficult to mold a container which has a partially thicker portion. In this respect, it has been customary to use glass as the material to manufacture a container which has a thicker bottom or a relatively thick barrel and which gives the visual impression of a high quality product. For instance, glass is normally used to manufacture a bottle container for liquid cosmetic material (e.g. Japanese Patent Application 9-215521).
However, in the bottle container made of glass as described above, surface irregularities or distortion often occurs on inner surface of the container during molding process, and it has been difficult to produce bottle containers with the same and uniform volume. When the bottle containers are different in volume and are used for liquid cosmetic material, the liquid surface is not maintained at a constant level even when the same quantity of liquid cosmetic material is filled in each container by using a filling machine. If the liquid level in a container is lower than that of another container, it looks as if the volume of the liquid cosmetic material inside the container is less than that of the other container. For this reason, it has been customary to fill the liquid cosmetic material into the bottle container by a manual operation until the liquid level reaches a predetermined position in each of the bottle containers. However, the manual filling operation of the liquid cosmetic material requires troublesome procedure and is even uneconomical because higher material cost is required when the liquid cosmetic material is expensive.